The aim of this paper is to present methods of digitally synthesising the sound generated by vibroacoustic systems with distributed parameters. A general algorithm was developed to synthesise the sounds of selected musical instruments with an axisymmetrical shape and impact excitation, i.e., Tibetan bowls and bells. A coupled mechanical-acoustic field described by partial differential equations was discretized by using the Finite Element Method (FEM) implemented in the ANSYS package. The presented synthesis method is original due to the fact that the determination of the system response in the time domain to the pulse (impact) excitation is based on the numerical calculation of the convolution of the forcing function and impulse response of the system. This was calculated as an inverse Fourier transform of the system’s spectral transfer function. The synthesiser allows for obtaining a sound signal with the assumed, expected parameters by tuning the resonance frequencies which exist in the spectrum of the generated sound. This is accomplished, basing on the Design of Experiment (DOE) theory, by creating a meta-model which contains information on its response surfaces regarding the influence of the design parameters. The synthesis resulted in a sound pressure signal in selected points in space surrounding the instrument which is consistent with the signal generated by the actual instruments, and the results obtained can improve them.

Aeromonas hydrophila is a valuable indicator of the quality of water polluted by sewage and pathogens that pose a risk for humans and cold-blooded animals, including fi sh. The main aim of this research was to evaluate anthropogenic pollution of river water based on genetic diversity of 82 A. hydrophila strains by means of RAPD, semi-random AP-PCR (ISJ) and the rep-BOX conservative repeats test. Genetic diversity of A. hydrophila was HT = 0.28 (SD = 0.02) for all DNA markers (RAPD, semi random and rep-BOX). None of the analyzed electrophoretic patterns was identical, implying that there were many sources of strain transmission. The presence of genes for aerolysin (aerA), hemolysin (ahh1) and the cytotoxic enzyme complex (AHCYTOGEN) was verifi ed for all tested strains, and drug resistance patterns for tetracycline, enrofl oxacin and erythromycin were determined. The most diverse A. hydrophila strains isolated from river water were susceptible to enrofl oxacine (HS = 0.27), whereas less diverse strains were susceptible to erythromycin (HS = 0.24). The presence of the multidrug resistance marker (ISJ4-25; 1100 bp locus) in the examined strains (resistant to three analyzed drugs) indicates that intensive fi sh cultivation affects the microbiological quality of river water.

There are typically two systems in use for sound reinforcement in open areas: the central, “wall of sound” system with speakers localized at the sides of the stage, and the zone system, in which additional speakers are introduced to obtain a uniform sound pressure level throughout the area of listening. In the past two decades the line array systems gained great popularity. The main purpose of their use is to obtain a uniformly distributed sound level throughout the listening area in order to achieve good speech intelligibility. The present paper aims to present an alternative and original method of sound reinforcement in open areas which is in contrast to the above solutions. This new method allows achieving a uniformly distributed sound pressure and good speech intelligibility in the area of interest, and also allows to gain spatial sound impression that accompanies sound reproduction in concert halls. Another advantage of the proposed system is the reduction of the sound level outside the area of interest, i.e. reduction of the noise level outside the area of listening.

One of the main issues of design process of HVAC systems and ventilation ducts in particular is correct modelling of coupling of the flow field and acoustic field of the air flowing in such systems. Such a coupling can be modelled in many ways, one of them is using linearised Euler equations (LEE). In this paper, the method of solving these equations using finite element method and open source tools is decribed. Equations were transformed into functional and solved using Python language and FEniCS software. The non-reflective boundary condition called buffer layer was also implemented into equations, which allowed modelling of unbounded domains. The issue, influence of flow on wave propagation, could be adressed using LEE equations, as they take non-uniform mean flow into account. The developed tool was verified and results of simulations were compared with analytical solutions, both in one- and two-dimensional cases. The obtained numerical results are very consistent with analytical ones. Furthermore, this paper describes the use of the developed tool for analysing a more complex model. Acoustic wave propagation for the backward-facing step in the presence of flow calculated using Navier-Stokes equations was studied.

17 November 2022 marks the centenary of the death of Jan Grzegorzewski – Orientalist, Slavist, publicist and social activist. The aim of this article is to highlight this figure and to show his activity in various areas of social and scientific life, especially his contribution to Polish Oriental studies. This somewhat forgotten but extremely interesting and colourful, although somewhat controversial, figure has still not received the comprehensive biographical treatment he fully deserves. Thanks to his extraordinary determination and commitment to his activities, Jan Grzegorzewski initiated the establishing of the first Polish scientific journal of Oriental studies, Rocznik Orientalistyczny, for which he also obtained funds. The first part of the first volume of Rocznik, covering the years 1914–1915, was published in 1915 in Cracow, and the second part (for the years 1916–1918) only in 1918. There is also no doubt that with his activities, both academic and journalistic, Jan Grzegorzewski contributed to the establishment of the first Polish Oriental studies in Poland, which took place in 1919 at the Jagiellonian University in Cracow. Analysing some of Grzegorzewski’s achievements from today’s perspective, one can venture to say that with the issues presented in his publications, he undoubtedly inspired many later Orientalists to set new research directions.

This work determined the solid-water distribution coefficient Kd, the Freundlich constant KF and the organic carbon normalized coefficient K0c of ibuprofen in natural, aquifer sediments. They are characterized as silt sediments with different clay and sand fraction contents varied in specific surface areas. Content of organic carbon and pH are on the same level. For determining sorption coefficients values of ibuprofen in sediments, its concentration was measured in the aqueous and calculated in the solid phase. Batch tests were conducted following OECD Guideline 106. The resulting Kd values ranged between 1.14 and 2.29 L/kg, ~ between 0.25 and 5.48 and Koc between 1.22 and 2.53 for ibuprofen in sediments SI and S2, respectively. These experiments proved that the presence of clay minerals beside organic carbon and pH might be relevant in sorption of ibuprofen in sediments. A comparison of experimentally determined Koc with modelled Koc calculated on the base of octanol-water partitioning coefficient K0w shows that the prediction of sorption behaviour cannot be based only on Kow· This is probably due to the fact that these approaches well describe hydrophobic interactions, but fail to predict sorption of polar and ionic compounds.

In the study we have focused on the distribution of several metals (Cr, As, Pb) and anions (Cr, NO3-) and their partition between pore (interstitial) waters and sediments sampled at three stations at the Dobczyce Reservoir which supplies the drinking water to inhabitants from the city of Kraków and its agglomeration. The results show considerable increase in concentrations of Pb and As in pore water samples, when compared to the bottom waters. Meaningful alternations in concentration were observed in case of pore water samples (Pb, As) and sediments (Cr, Pb, As), coming from three stations and their lateral sections. The possible relations between this phenomenon and the sediment characteristic as well as the Fe and Ca content, has been studied. Some comments on the seasonal variations of anion contents in water and pore water samples, are also provided. It was found that nitrates and sulphates show considerable variations.

Currently, overhead lines dominate in the Polish medium and low voltage distribution networks. Maintaining their high reliability constitutes a very important challenge, especially under the severely changing climate conditions. An overhead power line exposed to high ice and rime loads has been considered. Using the finite element method (FEM), mechanical reliability of the distribution infrastructure was examined under various atmospheric conditions. Loads under the stressful conditions of rime, ice and wind were determined for the weakest section of the 30 kV overhead line, which consisted of concrete poles and ACSR conductors. SAIDI and SAIFI reliability indices and costs were determined for several variants of object reconstruction. The results allowed for determination of a solution relying on relocating the cables of all lateral branches and main line ice protection, through a system based on a weather-coordinated increase of the electrical load. To verify the solution proposed, a field experiment was conducted. The experiment confirmed the effectiveness of the solution proposed that appears to be universal. The paper is a result of synergic cooperation of two academic teams, i.e. a mechanical and electrical power engineering one, and the distribution system operator (DSO).

The research covered the determination: of the numbers or hcicrorrophic bacteria: psychrophil ic, psychrctolcrant, mcsophilic and percentage participation or hemolytic bacteria and .ieromonas hydrophila (with acrolysinc and hcmolysine genes) in the waters of the Drwęca River depending on environmental Ilictors and fishery management. The mean quantities 01· hclcrotrophic bacteria (Ht'C) at 4, 14 and 2~°C ranged: O. 78-7.57-101, 1.40-6.65-101 and 1.93-16.23- 103 efuen -3, respectively. The percentage participation 01· hemolytic heterotrophic bacteria (HemPC) and A. hvdrophila among psychrophilic, psychrotolcrant, mcsophilic microorganisms determined at 4, 14, 28°C, ranged: 7.9-10.4, 6.8-12.2, 8.6-22.0 ,111d 1.1-6.4%, respectively. Statistically significant correlation between examined bacteria and temperature values, flows and O2 saturations confirm that the occurrence of those microorganisms depends on the degree of microbiological contamination of that ecosystem, resulting from the fishery management and environmental factors.